Method of tempering molding-sand.



UNITED STATES PATENT OFFICE.

GEORGE K. I-IOOPER, OF DEDI IAM, MASSACHUSETTS.

METHOD OF TEMPERING MOLDING-SAND.

$PEGIFIGATION fOrming part of Letters Patent N0. 678,488, dated July 16,1901. Application filed April 12, 1901. SeriaI N0. 56,591. (Nospecimens.)

To all whom it may concern.-

Be it known that I, GEORGE K. HOOPER, a citizen of the United States,and a resident of Dedham, in the countyof Norfolk and State ofMassachusetts,have invented a'new and Improved Methodof TemperingMolding-Sand, of which the following is a specification.

My invention consists of a new method of tempering molding-sand 'forfoundry purposes, whereby a determined initial amount of moisture isimparted to the mass of sand uni formly and to a desired degreethroughout,-

thus enabling the workman to dispense with the tentative and in manycases unsatisfactory mixing processes which have heretofore been invogue. v

Tempering molding-sand consists in bringing the mass of sand to adegreeof dampness which adapts it to the work of making molds for castings.The precise degree to. which molding-sand is moistened varies with theexperience and estimation of different foundry masters, and withinfairly narrow limits the moisture of tempering sand difiers in differentfoundries; but in all cases heretofore known to me the method with whichmolding-sand has been impregnated with moisture is as follows: Themolding-sand when turned out of the molds to be broken up and screenedis too dry for'use in molding and has to be moistened; As thesand passesthrough the various screening and mixing operations it absorbs more orless moisture, according to the condition of the atmosphere, andtherefore when the work of moistening is begun no one knows actually howmuch water to add to a given mass of sand. The moistening has been donein a very crude way, water being added to the mass of sand, which isthen mixed either by hand or machinery until the moisture is distributedas evenly and thoroughly as possible by such methods, when the workmantests the temper of the sand by feeling of it. If in his opinion it istoo dry, more Water is added and the mixing repeated. If it is too wet,a rudely-measured quantity of dry sand is thrown into the moist mass andthe mixing repeated, and by such methods as these the sand is graduallybrought to a condition which satisfies the operator. This requires ahigh degree of skill based upon long experience, and even then is notuniformly satisfactory, as the imperfections in castings testify.

My method of preparing molding-sand for moist. The degree to which thismoisture 6 may be brought may be satisfactorily regulated by regulatingthe charge of the moisture of the atmosphere in the room where thetempering is done. The man in charge by observing a hygrometer placed inthe room can readily produce the desired degree of charge of moisture inthe atmosphere by means of admitting vapor from steam-pipes or byatomizer-sprays which fill the air with finely-subdivided particles ofwater, and by noting the correspondence between a given indication ofthe hygrometer and the desired temper of the sand the operator can atall times produce and maintain an atmospheric condition perfectly suitedto the accomplish- 8o ment of his purpose. By this means the sand comesto the final tempering process in an exactly=determined condition ofmoisture,and the man in charge of the work knows beforehand exactly howmuch water to add to a given weight or bulk of sand. A short experiencewith the moisture-charged air enables the sand-temperer to measure outthe requisite quantity of water, add it to the initially-moistened themixing, confident that no further testing or manipulation will benecessary. All the tentative hand manipulation and rule-of thumbaddition of water is done away with.

The sand which goes to the molding-room is 5 practically uniform inquality and no poor castings need be expected to result fromimproperly-tempered sand. This method will be found especially valuablein foundries wherein a continuous=conveyer system of 100 The dry sandabsorbs moisture from 60 sand, and then proceed with molding and castingis employed which calls completing the moistening by adding to the forrapid and uniform delivery of tempered sand a quantity of water in bulk,the said sand to the molding department. quantity being proportionatelydetermined What I claim, and desire to secure by Let with reference tothe atmospheric moisture of 15 5 ters Patent, is-'- preparation.

The method of tempering molding-sand, SignedbymeatBoston,Massachusetts,this which consists of maintaining amoisture- 4th day of April, 1901.

charged atmosphere in aninclosed space, ma- GEORGE K. HOOPER. nipulatingthe sand in the said atmosphere, Witnesses: 10 thereby imparting to thesand a uniform ini- E. TOLSTOLL,

tial degree of moisture, and subsequently FRANK S. HARTNETT.

